Many contemporary telephone systems are capable of routing hundreds of calls per second, transferring calls to alternate locations, and conferencing additional parties into the initial telephone call. To test these telephone systems, bulk call generators have been developed. Bulk call generators typically comprise a call generator that uses DTMF (dual tone multi frequency) tones to call a System Under Test (SUT). A typical bulk call generator is capable of generating thousands of calls per hour in order to fully test the switching capability of the SUT.
Even newer telephone systems include interactive requests that instruct a caller to press specific keys on a DTMF touch tone pad in order to select services, business departments, or identified persons. Additional features have been developed including voice mail. Voice mail is a system permitting a person to leave an outgoing message indicating that he is away from his desk and requesting the caller to leave a message. Usually, the person can also indicate that the caller may dial "0" to get personal help from an operator. If the caller leaves a message, it is stored by the voice mail system for later retrieval. The person for whom the message was left can then call from any telephone and retrieve the message by keying in the correct sequence of keys on a DTMF touch tone pad.
Voice message systems are computer based systems. As these telephonic systems become more sophisticated and more capable, there is an increasing need to properly test the equipment while it is being developed and before it is shipped to the customer. Testing is important to insure quality and capability of the systems for delivery.
Current testing techniques described above, where simply a large numbers of calls are placed, do not adequately test these interactive and voice message feature telephone systems. What is needed is a call generator capable of storing and communicating a variety of audio and electronic information to a SUT, and capable of verifying proper storage of that information by the SUT.